Update at 1010 hours KST on Monday: this article has been amended to include a statement from PUST.

North Korean authorities detained a U.S. citizen by the name of Kim Hak-song on Saturday, according to reports by the state-run news agency KCNA on Sunday.

The arrest of Kim, who was reportedly detained on suspicion of committing “hostile acts” against the country, brings the number of U.S. citizens held as prisoners in North Korea to four.

Mr. Kim is reported to be linked to the Pyongyang University of Science and Technology (PUST).

“A relevant institution of the DPRK detained American citizen Kim